The present invention relates generally to air recirculating type surface cleaning devices, in which the recirculated air flow may be used to remove debris and/or moisture from the cleaning surface.
It is known to provide a recirculating type floor cleaning or drying apparatus in which at least some of the exhaust air stream is recirculated through a suction air stream. In U.S. Pat. No. 3,964,925, to Burgoon, an apparatus for cleaning carpets is disclosed having an exhaust air nozzle located near the vacuum nozzle. The device disclosed in Burgoon utilizes the heated exhaust air (from the vacuum motor) to aid in drying floor coverings. The exhaust air nozzle or opening of Burgoon, if provided, includes a moveable rear wall that pivots about a hinge. Burgoon also states that “the exhaust air nozzle can be eliminated.”
In U.S. Pat. No. 4,884,315, to Ehnert, a closed circuit vacuum apparatus having an air recirculation duct is disclosed. Ehnert discloses a device in which the recirculation air passes through the carpet to provide a pneumatic agitation process.
In U.S. Pat. No. 5,457,848, to Miwa, a recirculating type cleaner is disclosed having a dust collecting port including a suction port and an outlet in which downstream flow of a fan is recirculated, discharged through the outlet, and drawn into the suction port. Several devices said to be prior art are also discussed in Miwa. FIGS. 1A and 1B of the Miwa patent show a rotary brush and a rotating vibrator device, respectively, in the exhaust stream adjacent to the suction line. Miwa FIG. 1E shows an exhaust line adjacent to a much larger suction area. Miwa FIGS. 1C and 1D disclose a suction compartment surrounded on at least two sides by exhaust lines, where the exhaust is discharged at an angle in Miwa FIG. 1C. Miwa FIGS. 2B and 2C disclose prior art recirculating type cleaners with valves for diverting a portion of the air flow so that the recirculation may be less than 100%. FIGS. 3A and 3B of Miwa show a recirculating type cleaner having a central jet nozzle terminating at an outlet for discharging recirculating flow. A dust collecting head includes a suction port that surrounds the nozzle outlet.
In U.S. Pat. No. 5,392,492, to Fassauer, an air-floated vacuum cleaner is disclosed that includes an impeller and an agitator below the impeller. Air to lift this device is provided through a plurality of air inlet openings and discharged under pressure by a second air impeller and eventually to the surface of the floor.
In U.S. Pat. No. 3,268,942, to Rossnan, a suction cleaning nozzle is disclosed that utilizes the exhaust air from the machine discharged through a plurality of finger-like air directing tubes to comb and set up the carpet so that the suction action can remove the dust and dirt from the pile and the base of the floor covering.
In U.S. Pat. No. 5,553,347, to Inoue, et al., an upright floating vacuum cleaner is disclosed having a central exhaust surrounded by a suction air inlet port.
Although it's known to utilize exhaust air to assist in drying and debris removal from floor coverings in a recirculating cleaner, there exists a need for an air recirculating type cleaning device that utilizes the collective energy of both the exhaust and suction lines to obtain superior results in less time and that conserves energy resources in the process.